Fine roots biomass and morphology in a chronosequence of young Pinus sylvestris stands growing on a reclaimed lignite mine spoil heap

The morphology of fine roots ( 2 mm diameter) as well as fine and coarse root biomass was investigated in a chronosequence consisting of 6-, 9-, 11-, 15-, 17- and 20-year-old Scots pine (Pinus sylvestris) stands growing on a reclaimed lignite mine spoil heap. Core method of destructive root sampling was used to establish whether root morphology and biomass varied with stand age in the upper 20 cm of soil. Fine root biomass ranged from 0.78 to 3.11 Mg ha-1, coarse root biomass ranged from 0.82 to 2.74 Mg ha-1, whereas root necromass ranged from 1.03 Mg ha-1 to 2.87 Mg ha-1 in the chronosequence studied. Fine root diameter as well as length, projected area, and surface area expressed per unit area increased significantly with stand age. Moreover, our study revealed that when stand age increases, specific fine root biomass increases, whereas specific root length and area decreases. The results support our hypothesis that stand age has an effect on standing fine root biomass and morphology.